The attack happened on Tuesday evening in Mannedorf on Lake Zurich, around 20 kilometres southeast of Switzerland’s largest city, the Zurich cantonal police said.

A 19-year-old suspect has been arrested.

“On Tuesday evening a woman was attacked and fatally injured by a man in Mannedorf,” police said, adding that the woman had been out jogging.

On Thursday, authorities identified the victim as “a 35-year-old Swiss woman.” No further details have been given, though the Swiss media said her name was Anna, and she lived in the neighbourhood.

The man confessed during questioning by the public prosecutor, but no motive has so far been established.

“Shortly before 8:00 pm (1800 GMT), passers-by reported a man in Alma Park who was running around naked, screaming and physically attacking other people.

“The emergency services who quickly arrived on site found a seriously injured woman lying on the ground.

“Despite immediate resuscitation, the woman died from her serious injuries.

“The suspected perpetrator, a 19-year-old Swiss, who was also found on site, was arrested by the police.”

The man confessed to killing the jogger during questioning by the public prosecutor. He has no previous police record for violent crimes in the canton of Zurich.

“Due to the ongoing criminal proceedings and for reasons of privacy protection, no further information can currently be disclosed beyond the content of this media release,” police added.

‘He stripped naked and screamed’

An eyewitness Nebojsa Dimic described the chaotic scene in the park to Swiss media.

He said that the alleged perpetrator “initially sat peacefully with his girlfriend by the lake. But suddenly I heard him scream.”

The man calmed down briefly, but then ran into the woods.

“He took off his clothes there and started screaming again.”

Dimic said he then alerted the police. Later, screams from women and cars honking could be heard.

Alma Park, where the murder happened, is known as a place for summer picnics.

The small, grassy park dotted with trees was open to the public on Wednesday, with two police officers standing on the lakeside path near the scene of the attack.

After police questioning, the arrested suspect will be referred to the public prosecutor for serious violent crime, the police said.

Police told Switzerland’s Keystone-ATS news agency that the attacker lightly injured a second person, while it was still unknown whether the perpetrator used a weapon.

The Zurich Forensic Science Institute, the leading body for forensic expertise in Switzerland, collected evidence, the police said, while Zurich University’s Institute of Forensic Medicine is also involved in the investigation.

Fire crews, an ambulance, and emergency doctor and the air rescue service were also called in, the police said.

A German-speaking village, Mannedorf has nearly 12,000 residents, according to the latest government statistics, and is overlooked by a white-painted Reformed church.

Next to a harbour, Alma Park surrounds the Villa Alma, a neo-Gothic residence built for the industrialist Emil Staub, who expanded the family business into Switzerland’s most important leather production plant.

It was named after his wife, who lived there until her death in 1970, outliving her husband by 41 years. It was sold by her heirs and is now used as a retirement home.

With reporting from AFP